Social top-down response modulation (STORM): a model of the control of mimicry in social interaction

Human social interaction is complex and dynamic(Hari and Kujala,2009).Individuals communicate with each other by means of multiple verbal and nonverbal behaviors,which rapidly change from moment to moment.Unraveling mechanisms underlying the subtlety of social behaviors is important for our understanding of the nature of human social interaction. One remarkable nonverbal behavior during social interactions is spontaneous mimicry(van Baarenetal.,2009). People have a tendency to unconsciously imitate other’s behaviors(Chartr and and van Baaren,2009). In the past decade, this spontaneous mimicry has become the key focus of research in socialpsychology and cognitive neuroscience(Heyes,2009),and has been regarded as a paradigm for exploring the complexity of human social interaction.Investigations of the causes,consequences and brain basis of mimicry have been widely carried out(Chartr and and van Baaren,2009). For example,socialpsychology suggests that mimicry has positive consequences on social interaction;it increases liking and affiliation between interaction partners and makes communication more smooth and enjoyable(Chartr and and Bargh,1999). Cognitive neuroscience further suggests that mimicry is based on the mirror neuron system(MNS)(Catmur et al., 2008, 2009; Heyes, 2011a). This system provides a direct link between perception and action where observing an action automatically activates the motor representation of that action(Brass and Heyes,2005)and this link is most likely developed by associative sequence learning(“the ASL theory,” Heyes,2001,2011a; Catmur et al.,2007,2008,2009). However,two key questions still remain unclear. First,what is the purpose of mimicry? Although the ASL theory clearly elucidates how we develop the ability to mimic,it does not directly explain under what circumstances we will mimic and why we mimic to different degrees in different situations. Second,what brain mechanisms control and implement mimicry responses? In this article we aim to address these two questions by reviewing cutting-edge research on the control of mimicry by social signals. In the first part,we give a brief outline of past theories on the purpose of mimicry and emphasize that mimicry is a strategy for social advantage.We provide evidence that mimicry changes depending on the social context[i.e.,social top-down response modulation (STORM)], and suggest that this subtle control may reflect a Machiavellian strategy for enhancing one’s social standing. In the second part, we move to a neuroscience point of view and examine the information processing systems underlying the control of mimicry. We suggest that medial pre-frontal cortex(mPFC)plays a key role in the control of mimicry in social contexts. Finally, we discuss the importance of the STORM model of mimicry in our understanding of social interaction and social cognition. We argue that subtly controlling when and who to mimic is essential to human competence in social interactions and suggest that impairment of this function could lead to social-communication disorders such as autism

Audience effects: what can they tell us about social neuroscience, theory of mind and autism?

An audience effect arises when a person’s behaviour changes because they believe someone else is watching them. Though these effects have been known about for over 110 years, the cognitive mechanisms of the audience effect and how it might vary across different populations and cultures remains unclear. In this review, we examine the hypothesis that the audience effect draws on implicit mentalising abilities. Behavioural and neuroimaging data from a number of tasks are consistent with this hypothesis. We further review data suggest that how people respond to audiences may vary over development, personality factors, cultural background and clinical diagnosis including autism and anxiety disorder. Overall, understanding and exploring the audience effect may contribute to our models of social interaction, including reputation management and mentalising

Testing the relationship between mimicry, trust and rapport in virtual reality conversations

People mimic each other’s actions and postures during everyday interactions. It is widely believed this mimicry acts as a social glue, leading to increased rapport. We present two studies using virtual reality to rigorously test this hypothesis. In Study 1, 50 participants interacted with two avatars who either mimicked their head and torso movements at a 1 or 3 second time delay or did not mimic, and rated feelings of rapport and trust toward the avatars. Rapport was higher towards mimicking avatars, with no effect of timing. In Study 2, we aimed to replicate this effect in a pre-registered design and test whether it is modulated by cultural ingroup-outgroup boundaries. Forty participants from European or East Asian backgrounds interacted with four avatars, two of European appearance and two of East Asian appearance. Two avatars mimicked while the other two did not. We found no effects of mimicry on rapport or trust ratings or implicit trust behaviour in a novel maze task, and no effects of group status or interactions. These null results were calculated in line with our pre-registration. We conclude that being mimicked does not always increase rapport or trust, and make suggestions for future directions

Moving higher and higher: imitators' movements are sensitive to observed trajectories regardless of action rationality

Humans sometimes perform actions which, at least superficially, appear suboptimal to the goal they are trying to achieve. Despite being able to identify these irrational actions from an early age, humans display a curious tendency to copy them. The current study recorded participants' movements during an established imitation task and manipulated the rationality of the observed action in two ways. Participants observed videos of a model point to a series of targets with either a low, high or 'superhigh' trajectory either in the presence or absence of obstacles between her targets. The participants' task was to watch which targets the model pointed to and then point to the same targets on the table in front of them. There were no obstacles between the participants' targets. Firstly, we found that the peak height of participants' movements between their targets was sensitive to the height of the model's movements, even in the 'superhigh' condition where the model's action was rated as irrational. Secondly, participants showed obstacle priming-the peak height of participants' movements was higher after having observed the model move over obstacles to reach her targets, compared to when there were no obstacles between her targets. This suggests that participants code the environment of co-actors into their own motor programs, even when this compromises the efficiency of their own movements. We discuss the implications of our findings in terms of theories of imitation and obstacle priming

How can the study of action kinematics inform our understanding of human social interaction?

The kinematics of human actions are influenced by the social context in which they are performed. Motion-capture technology has allowed researchers to build up a detailed and complex picture of how action kinematics vary across different social contexts. Here we review three task domains-point-to-point imitation tasks, motor interference tasks and reach-to-grasp tasks-to critically evaluate how these tasks can inform our understanding of social interactions. First, we consider how actions within these task domains are performed in a non-social context, before highlighting how a plethora of social cues can perturb the baseline kinematics. We show that there is considerable overlap in the findings from these different tasks domains but also highlight the inconsistencies in the literature and the possible reasons for this. Specifically, we draw attention to the pitfalls of dealing with rich, kinematic data. As a way to avoid these pitfalls, we call for greater standardisation and clarity in the reporting of kinematic measures and suggest the field would benefit from a move towards more naturalistic tasks

Learning to tie the knot: The acquisition of functional object representations by physical and observational experience

Here we examined neural substrates for physically and observationally learning to construct novel objects, and characterized brain regions associated with each kind of learning using fMRI. Each participant was assigned a training partner, and for five consecutive days practiced tying one group of knots (“tied” condition) or watched their partner tie different knots (“watched” condition) while a third set of knots remained untrained. Functional MRI was obtained prior to and immediately following the week of training while participants performed a visual knot-matching task. After training, a portion of left superior parietal lobule demonstrated a training by scan session interaction. This means this parietal region responded selectively to knots that participants had physically learned to tie in the post-training scan session but not the pre-training scan session. A conjunction analysis on the post-training scan data showed right intraparietal sulcus and right dorsal premotor cortex to respond when viewing images of knots from the tied and watched conditions compared to knots that were untrained during the post-training scan session. This suggests that these brain areas track both physical and observational learning. Together, the data provide preliminary evidence of engagement of brain regions associated with hand-object interactions when viewing objects associated with physical experience, and with observational experience without concurrent physical practice

The virtual maze: A behavioural tool for measuring trust

Trusting another person may depend on our level of generalised trust in others, as well as perceptions of that specific person's trustworthiness. However, many studies measuring trust outcomes have not discussed generalised versus specific trust. To measure specific trust in others, we developed a novel behavioural task. Participants navigate a virtual maze and make a series of decisions about how to proceed. Before each decision, they may ask for advice from two virtual characters they have briefly interviewed earlier. We manipulated the virtual characters' trustworthiness during the interview phase and measured how often participants approached and followed advice from each character. We also measured trust through ratings and an investment game. Across three studies we found participants followed advice from a trustworthy character significantly more than an untrustworthy character, demonstrating the validity of the maze task. Behaviour in the virtual maze reflected specific trust rather than generalised trust, whereas the investment game picked up on generalised trust as well as specific trust. Our data suggests the virtual maze task may provide an alternative behavioural approach to measuring specific trust in future research, and we demonstrate how the task may be used in traditional laboratories

Effects of being watched on self-referential processing, self-awareness and prosocial behaviour

Reputation management theory suggests that our behaviour changes in the presence of others to signal good reputation (audience effect). However, the specific cognitive mechanisms by which being watched triggers these changes are poorly understood. Here we test the hypothesis that these changes happen because the belief in being watched increases self-referential processing. We used a novel deceptive video-conference paradigm, where participants believe a video-clip is (or is not) a live feed of a confederate watching them. Participants completed four tasks measuring self-referential processing, prosocial behaviour and self-awareness under these two belief settings. Although the belief manipulation and self-referential effect task were effective, there were no changes on self-referential processing between the two settings, nor on prosocial behaviour and self-awareness. Based on previous evidence and these findings, we propose that further research on the role of the self, social context and personality traits will help elucidating the mechanisms underlying audience effects

A review of theories and methods in the science of face-to-face social interaction

For most of human history, face-to-face interactions have been the primary and most fundamental way to build social relationships, and even in the digital era they remain the basis of our closest bonds. These interactions are built on the dynamic integration and coordination of verbal and non-verbal information between multiple people. However, the psychological processes underlying face-to-face interaction remain difficult to study. In this Review, we discuss three ways the multimodal phenomena underlying face-to-face social interaction can be organized to provide a solid basis for theory development. Next, we review three types of theory of social interaction: theories that focus on the social meaning of actions, theories that explain actions in terms of simple behaviour rules and theories that rely on rich cognitive models of the internal states of others. Finally, we address how different methods can be used to distinguish between theories, showcasing new approaches and outlining important directions for future research. Advances in how face-to-face social interaction can be studied, combined with a renewed focus on cognitive theories, could lead to a renaissance in social interaction research and advance scientific understanding of face-to-face interaction and its underlying cognitive foundations

Do Beliefs About Whether Others Can See Modulate Social Seeking in Autism?

Autistic people process gaze differently than typical people, but it is not yet clear if these differences lie in the processing of eye-shapes or the belief in whether others can see (perceptual mentalizing). We aimed to investigate whether these two models of gaze processing modulate social seeking in typical and autistic adults. We measured preferences of participants to view videos of an actress with visible or hidden eyes, who can or cannot see out. While typical participants preferred videos where the actress can see through and has visible eyes, autistic people showed no preference for these videos. These findings are discussed in the context of perceptual mentalizing and the social motivation theory of autism